Tag Archives: Heike Ebendorff-Heidepriem

Sensors for calcium ion

15 June 2017:

Researchers from CNBP (lead author Dr Sabrina Heng pictured), have just had a paper published, reporting on three new spiropyran-based reversible sensors for calcium ion.

Journal: Sensors and Actuators B: Chemical.

Publication title: Photoswitchable calcium sensor: ‘On’–‘Off’ sensing in cells or with microstructured optical fibers.

Authors: Sabrina Heng, Adrian M. Mak, Roman Kostecki, Xiaozhou Zhang, Jinxin Peia, Daniel B. Stubing, Heike Ebendorff-Heidepriema, Andrew D. Abell.

Abstract: Calcium is a ubiquitous intracellular signaling ion that plays a critical role in the modulation of fundamental cellular processes. A detailed study of these processes requires selective and reversible sensing of Ca2+ and an ability to quantify and monitor concentration changes in a biological setting. Three new, rationally designed, synthesized and photoswitchable spiropyran-based reversible sensors for Ca2+ are reported. Sensor 1a is highly selective for Ca2+ with an improved profile relative to the other two analogues, 1b and 1c. Formation of the merocyanine–Ca2+ complex is proportional to an increase in Ca2+ released from HEK293 cells on stimulation with ionomycin. The photophysical processes surrounding the binding of Ca2+ to compound 1a were further explored using computational methods based on density functional theory (DFT). The ability of sensor 1a to bind Ca2+ and photoswitch reversibly was also characterized using silica suspended-core microstructured optical fiber (SCF). These SCF experiments (with 100 nM Ca2+) represent a first step toward developing photoswitchable, minimally invasive and highly sensitive Ca2+ sensing platforms for use in a biological setting.

The paper is accessible online.

Tuning third harmonic light

27 April 2017:

Researchers from CNBP and The Institute of Photonic Technology (lead author Stephen Warren-Smith pictured), have just had a paper published on tuning third harmonic light generated within exposed-core fibres.

Journal: Optics Letters.

Publication title: Nanofilm-induced spectral tuning of third harmonic generation.

Authors: Stephen C. Warren-Smith, Mario Chemnitz, Henrik Schneidewind, Roman Kostecki, Heike Ebendorff-Heidepriem, Tanya M. Monro and Markus A. Schmidt.

Abstract: Intermodal third-harmonic generation using waveguides is an effective frequency conversion process due to the combination of long interaction lengths and strong modal confinement. Here we introduce the concept of tuning the third harmonic phase-matching condition via the use of dielectric nanofilms located on an open waveguide core. We experimentally demonstrate that tantalum oxide nanofilms coated onto the core of an exposed core fiber allow tuning the third harmonic wavelength over 30 nm, as confirmed by qualitative simulations. Due to its generic character, the presented tuning scheme can be applied to any form of exposed core waveguide and will find applications in fields including microscopy, biosensing, and quantum optics.

The paper is accessible online.

CNBP talks to the pollies at SmP

24 March 2017:

A chance to talk science with Australian politicians and policy influencers was an opportunity seized by CNBP with Centre Investigator Prof Heike Ebendorff-Heidepriem and Centre Research Fellow Dr Andrew Care both in attendance at the annual ‘Science meets Parliament’ (SmP) event, Canberra, 21-22 March, 2017.

Established by Science and Technology Australia, SmP provides 200 scientists with a unique professional development opportunity to get a clear sense of the competing rationalities of science, politics and public policy. The two-day gathering also includes a day at Parliament House, where delegates get the chance to meet privately with parliamentarians.

As part of this activity, Prof Ebendorff-Heidepriem met with Senator Chris Back and Senator Chris Ketter, and also spoke with Shadow Minister of Defence, Richard Marles. In addition, she spoke with many researchers and entrepreneurs from both the University and industry sectors.

“Improving collaboration between the research community and industry was a hot topic in many of the discussions that I had”, said Heike. “Particularly in my meeting with Senator Chris Back. People were also extremely excited about our approach, in using fibres and light to create exciting new windows into the body.”

CNBP’s Dr Andrew Care met with Opposition Leader Bill Shorten’s advisor, discussing gender equality and early education for STEM and also touching on ECR opportunities and improving research and industry ties. He also met MP Adam Bandt, the Greens spokesperson for science.

“Overall it was an extremely rewarding experience,” says Andrew. “Attending SmP gave me the opportunity to explore the political process and to network with many other researchers from academia, industry, and governance. It was fantastic to see science and innovation so high on the government’s agenda.”

A full round up from both days of SmP can be found on the STA web site – Day 1 and Day 2.

Below – MP Adam Bandt and CNBP’s Dr Andrew Care.


Heike Ebendorff-Heidepriem gives seminar at USYD

Heike Ebendorff Low Res Edit 018025 May 2016:

CNBP Investigator, Professor Heike Ebendorff-Heidepriem has presented a seminar at the Institute of Photonics and Optical Science at the University of Sydney on 25 May 2016.

Heike’s talk title was: Taming the Light in Optical Fibres for Sensing.

Abstract – This talk reviews the light-based sensing approaches developed at the Institute for Photonics and Advanced Sensing (IPAS) at Adelaide University in the field of chemical and physical sensing utilizing novel light sources and optical fibres. Depending on the intended application, a host of sensing modalities have been utilized including labelled fluorescence techniques, and label-free methods such as spectroscopy, surface plasmon resonance, fiber Bragg gratings, and Raman scattering. The use of various functionalization techniques adds specificity to ions and molecules. Microstructured and hybrid material optical fibers offer important benefits compared to traditional techniques such as small sample volumes, high sensitivity, remote sensing and multiplexing.

CNBP at US-Australia Technical Exchange meeting

Heike Ebendorff Low Res Edit 018023 May 2016:

Professor Heike Ebendorff-Heidepriem (CNBP Investigator), Dr Lindsay Parker (CNBP Research Fellow) and Dr Andrew Care (CNBP Research Fellow) spoke at the US-Australia Enabling Technologies Technical Exchange Meeting 2016 at UNSW in Sydney on 23-24 May 2016.

Heike’s talk was: “Pushing the Limits in Glass Properties and Structures for Laser, Sensing and Nonlinearity Applications.”

Lindsay’s talk was: “Illuminating mRNA and proteins in new ways with nanoparticles and chemical conjugates.”

Andrew’s talk was: “Developing a platform technology for the self-assembly of functional nanoparticles.”

The purpose of the Technical Exchange is to explore and potentially develop new areas of basic research collaboration between Australian and US participants.

Additional meeting information is available online.


Sensing Zn2+ ions in biological samples

sabrina213 May 2016:

CNBP researchers have created nanoscale biosensors that are capable of sensing Zn2+ ions in biological samples. Such sensors have potential application in disease diagnosis and study, as well as in environmental sensing. The study was published in the journal ACS Applied Materials and Interfaces, May 13th, 2016.

Publication title: Microstructured Optical Fiber-based Biosensors: Reversible and Nanoliter-Scale Measurement of Zinc Ions.

Authors: Sabrina Heng (pictured), Christopher A. McDevitt, Roman Kostecki, Jacqueline R. Morey, Bart A. Eijkelkamp, Heike Ebendorff-Heidepriem, Tanya M. Monro, and Andrew D. Abell.

Sensing platforms that allow rapid and efficient detection of metal ions would have applications in disease diagnosis and study, as well as environmental sensing. Here, we report the first microstructured optical fiber-based biosensor for the reversible and nanoliter-scale measurement of metal ions. Specifically, a photoswitchable spiropyran Zn2+ sensor is incorporated within the microenvironment of a liposome attached to microstructured optical fibers (exposed-core and suspended-core microstructured optical fibers). Both fiber-based platforms retains high selectivity of ion binding associated with a small molecule sensor, while also allowing nanoliter volume sampling and on/off switching. We have demonstrated that multiple measurements can be made on a single sample without the need to change the sensor. The ability of the new sensing platform to sense Zn2+ in pleural lavage and nasopharynx of mice was compared to that of established ion sensing methodologies such as inductively coupled plasma mass spectrometry (ICP-MS) and a commercially available fluorophore (Fluozin-3), where the optical-fiber-based sensor provides a significant advantage in that it allows the use of nanoliter (nL) sampling when compared to ICP-MS (mL) and FluoZin-3 (μL). This work paves the way to a generic approach for developing surface-based ion sensors using a range of sensor molecules, which can be attached to a surface without the need for its chemical modification and presents an opportunity for the development of new and highly specific ion sensors for real time sensing applications.

The paper is available online.

Latest paper published in Scientific Reports

Yinlan-Ruan-(3)22 February 2016:

CNBP researchers have published a paper in the journal Scientific Reports. Demonstrated is a novel but simple method for creating transparent conductive reduced graphene oxide film onto microstructured silica fibres for potential optoelectronic applications.

Title: Integration of conductive reduced graphene oxide into microstructured optical fibres for optoelectronics applications.

Authors: Yinlan Ruan, Liyun Ding, Jingjing Duan, Heike Ebendorff-Heidepriem & Tanya M. Monro.

Abstract: Integration of conductive materials into optical fibres can largely expand functions of fibre devices including surface plasmon resonator/metamaterial, modulators/detectors, or biosensors. Some early attempts have been made to incorporate metals such as tin into fibres during the fibre drawing process. Due to the restricted range of materials that have compatible melting temperatures with that of silica glass, the methods to incorporate metals along the length of the fibres are very challenging. Moreover, metals are nontransparent with strong light absorption, which causes high fibre loss. This article demonstrates a novel but simple method for creating transparent conductive reduced graphene oxide film onto microstructured silica fibres for potential optoelectronic applications. The strongly confined evanescent field of the suspended core fibres with only 2 μW average power was creatively used to transform graphene oxide into reduced graphene oxide with negligible additional loss. Existence of reduced graphene oxide was confirmed by their characteristic Raman signals, shifting of their fluorescence peaks as well as largely decreased resistance of the bulk GO film after laser beam exposure.

The paper is open access and available online.

Drawing tubular fibres

Heike Ebendorff Low Res Edit 018015 December 2015:

CNBP researchers A/Prof Heike Ebendorff-Heidepriem and Dr Herbert Foo feature in this latest paper published in Optical Materials Express – ‘Drawing tubular fibres: experiments versus mathematical modelling.’

Abstract – 
A series of six experiments drawing tubular fibres are compared to some recent mathematical modelling of this fabrication process. The importance of fibre tension in determining the internal geometry of the fibre is demonstrated, confirming a key prediction of the models. There is evidence of self-pressurisation of the internal channel, where an additional pressure is induced in the internal channel as the fibre is drawn, and the dependence of the magnitude of this pressure on fibre tension is discussed. Additionally, there is evidence that the difference between the glass and furnace temperatures is proportional to the furnace temperature and dependent on the preform geometry.

Further paper information is available online.